This invention relates to a system for the electronic storage and retrieval of expressions and linguistic information. More particularly, it pertains to a method and apparatus for the storage of digital signals representative of linguistic expressions, e.g., words, based upon the grammatical and inflectional characteristics of the expressions. The invention also pertains to a method and apparatus for determining the grammatical type and inflection aspects of an input expression. The invention also pertains to a method and apparatus for the electronic generation of expressions linguistically related, both grammatically and inflectionally, to an input expression. The invention has application in the field of text processing, for example, in a word processor.
In general, text processing systems facilitate the preparation of printed documents. Early text processing systems provided simple text formatting features, e.g., text justification, automatic hyphenation, and tabulation. Subsequent systems provided spelling verification procedures to flag incorrectly spelled words. More recently, these systems have incorporated automatic word correction facilities.
A recent advance in text processing systems is the inclusion of a so-called "electronic thesaurus," i.e., a system for generating a list of words linguistically related, i.e., synonymous or antonymous, to a designated word. One such system is described by Rosenbaum et al, U.S. Pat. No. 4,384,329. That system incorporates an ordered vocabulary of linguistic expressions and an NxN binary matrix defining the relationship between expressions in the vocabulary. An input expression is compared with successive entries of the vocabulary to find a match. Access to the corresponding entry of the matrix provides the address of synonymous and antonymous expressions. In part, the utility of the Rosenbaum et al system is constrained by the method with which vocabulary expressions are stored: each expression is stored in its entirety. Further, the system does not provide grammatical and inflectional information for the entries. Consequently, the system is not understood to recognize, for example, the word "came" to be the past tense inflectional form of the verb "to come". Another drawback of the system is that expressions identified as being synonymous and antonymous with the input expression are generated without regard to the grammatical or the inflectional classification of that input expression.
An object of this invention, accordingly, is to provide an improved system for the storage and retrieval of expressions and linguistic information for use in automated text processing equipment.
Another object of the invention is to provide a method and apparatus for the space-efficient storage of digital signals representative of expressions and linguistic information.
A further object of the invention is to provide a system for the rapid electronic determination of the grammatical and the inflectional classification of an input expression.
Still further, an object of the invention is to provide an improved electronic thesaurus, which is capable of producing a list of expressions both grammatically and inflectionally related to an input expression, i.e., being directly substitutable for the input expression without requiring user intervention for inflecting those related expressions.
Other objects of the invention are evident in the following description.